Goh catching a bunch of really strong pokemon or easily, that a beginning trainer that barely trains like him has any business catching one's like Darmanitan or that giant Golurk so damn early, especially since Goh barely contributed to the latter fight. And then there's him catching legendaries, he had no business catching Suicune, especially someone who just started their damn trainer career. Frankly beating those hunters, and freeing it by hand would have been better writing, but hey Goh has to get what he wants even though he doesn't deserve it. Same with Regieleki.
Also why the hell did they think it was a good idea to have Ash and his other Pokemon (other than Pikachu) take a backseat to develop/experiment with Goh as a secondary protagonist and advertise that problematic mobile app (which failed btw), especially since they were just gonna move on to new protags, now where starting from zero, with a lot of unused and wasted potential for Ash now.
The fact that this garbage season is Ash's last season. Really, they thought the season was the one to end his Journey, where 90% of the attention of those in charge was spent on Goh, or those crappy slapstick episodes.
Finally I hated the prize machine, part of Trio's charm was their relationship with their pokemon that they caught
minor or debatable problems:
Ash not catching anything new after Dracovish (That was 86 episodes ago btw)
Ash having multiples of the same type, If they're gonna restrict Ash to just using just thevfive he catches, plus Pikachu, give him more variety in types, and on top of that not just speedy attackers either.
Even though they didn't get the development they needed, it still got boring and stagnant really fast seeing Ash the same team for 86 episodes. I also think he should have used reserves as well as new additions, especially since that means some of his unevolved pokemon could have finally evolved, like his corphish, or the majority of his Unova Pokemon. Heck the writers could have made it so that he could have had all three Hisuian starters.
That and he didn't get more Galar rep either, especially since this was gen 8 for goodness sakes, and a lot. Either Sobble or Grookey should have gone too Ash, hell maybe both at this point considering how poorly they were handled under Goh.